The Design, Analysis and Data Management (DADM) Core will provide biostatistical and data management support to IDS-1, IDS-2, IDS-3 the pilot projects, and other projects funded by non-OAIC sources. Specific aims are: 1) to develop appropriate research designs, measurement methodologies and randomization strategies; 2) to assist investigators in the conduct of studies by addressing issues of subject recruitment and retention, monitoring study progress, data collection procedures, adherence to protocol, and adverse events; 3) to develop appropriate instruments for data collection, including computerized direct entry and paper-based batch instruments; 4) ensure high standards of data quality across projects; 5) maintain systems to acquire utilization and cost data from hospitals and other agencies; 6) maintain, operate and provide user support for shared database and computing resources; 7) select or develop state-of-the art analysis techniques for each supported project; 8) participate in the writing of abstracts and manuscripts; 9) document all master data files, data elements and algorithms for composite scale construction; and 10) train and supervise junior faculty data management and anlysis methodologies. The DADM Core is led by Dr. Robert Makuch, Professor of Biostatistics and an expert in clinical trials methodology. The Associate Director is Mr Peter Charpentier, Senior Research Programmer, who is an expert in data base systems and scientific programming. Additional high-level biostatistical support will be provided by Dr. Peter Peduzzi, Professor of Biostatistics and Assistant Chief of the Cooperative Studies Program at the West Haven VAMC Branch, and by Dr. Theresa O'Connor, Associate Research Scientist in Anesthesiology. Dr. John Rizzo, Associate Professor of Health Economics and Director of the Yale Economic Evaluation Center, will be responsible for the cost-effectiveness analyses for the proposed IDS studies. The DADM data management staff includes one data manager, one data management operations/documentation assistant, and one data entry specialist. The DADM workgroup has experience and expertise in all of the methodologies and operational procedures that will be required to support the proposed IDS and Pilot projects.